1. Field of the Invention
The present invention relates to the devices employed for joining together two successive portions of a conveyor belt.
2. Description of the Prior Art
A joint of this type is usually formed by fitting two complementary series of metallic belt-fasteners on the ends of the two portions to be joined together, then coupling said two series of fasteners by means of a hinge-pin which is passed through the entire set of interengaged hinge-knuckles of these fasteners. As a general rule, the hinge-pin is formed by a cable made up of twisted wires which have the function of endowing the cable with the requisite degree of flexibility in the transverse direction. This condition is in fact essential in order to ensure that the conveyor belt can assume an inwardly curved transverse profile during service and thus take the shape of a trough on the belt-supporting rollers.
During recent years, a certain number of solutions have been devised for increasing the mechanical strength of belt-fasteners of the type under consideration together with their hinge-knuckles. However, it has not been possible up to the present time to produce a similar reinforcement of the connecting hinge-pins of said belt-fasteners by reason of the very fact that these latter must possess suitable flexibility in the transverse direction. In consequence, these hinge-pins constitute the weak point of belt-coupling devices of the type considered.
In order to correct some of the defects of the connecting hinge-pins of these devices, a certain number of solutions have already been proposed. Thus German Pat. No. 805,144 relates to a coupling pin of this type on which are welded metal sleeves disposed at predetermined intervals. By means of these sleeves, it is possible to cut a coupling pin of this type at an intermediate point without separating the wires from each other. However, this solution fails to achieve any real increase in mechanical strength of the coupling pin.
German Pat. No. 926,645 describes a hinge-pin of the type under consideration over which are threaded a series of metal sleeves arranged in succession. The presence of these sleeves protects the hinge-pin from any direct contact with the knuckles of the coupling elements while nevertheless retaining a certain degree of flexibility of said hinge-pin in order to permit troughing of the conveyor belt. However, this solution does not really have the effect of enhancing the mechanical strength of the hinge-pin.
U.S. Pat. No. 2,962,782 and French Pat. No. 720,857 describe hinge-pins of the type under consideration in which provision is made for a protective outer sheath of flexible material. This design concept is likewise intended to achieve protection of the hinge-pin but does not result in higher mechanical strength.
Similar arrangements are also found in the case of the hinge-pins described in German Pat. Nos. 2,240,013 and 2,507,474. Again in this instance, protective metal sleeves are thus passed over hinge-pins of the type considered and the same applies to German Pat. No. 926,645.